The present invention generally relates to transducer element assemblies, and more particularly to a transducer element assembly having a transducer element for recording and/or reproducing an information signal on and/or from a rotary recording medium.
Currently an information signal is recorded on and reproduced from various recording mediums. As systems in which a transducer element records and/or reproduces the information signal by making direct contact with a recording surface of the recording medium, there are the magnetic recording and/or reproducing system and the electrostatic capacitance type recording and/or reproducing system, for example, and a magnetic head, a reproducing stylus and the like are used as the transducer element. When reproducing the information signal from the rotary recording medium such as a disc, it is necessary to carry out a tracking control so that the transducer element accurately scans over an intended track. The transducer element is provided on a tip end of a cantilever, and a root end of the cantilever is driven and displaced by an actuator so as to displace the transducer element in a direction of the width of the track to thereby carry out the tracking control.
A first example of the conventional transducer element assembly comprises a generally V-shaped cantilever and a transducer element provided at the valley part of the V-shaped cantilever. A pair of arms of the cantilever are mounted on a support plate via rubber dampers, and the support plate is driven and displaced by the actuator. The transducer element makes contact with the recording surface of the rotary recording medium with a predetermined contact pressure due to the resiliency of the rubber dampers. Such a transducer element assembly is shown in FIG. 15 of the U.S. Pat. No. 4,160,268, for example.
However, according to this first example of the conventional transducer element assembly, there is a problem in that torsion and vibration are easily generated at the transducer element due to the resonance of a mechanical resonant system constituted by the cantilever and the rubber dampers. In addition, when a loop gain of a tracking control system in a recording and/or reproducing apparatus is set to a large gain, there is a possibility of oscillation at high frequencies. Hence, it is possible to consider using rubber dampers having an extremely large stiffness, but in this case, the contact pressure of the transducer element on the recording surface of the rotary recording medium becomes too large. When the contact pressure of the transducer is large, the serviceable life of the transducer element is shortened, and the recording surface of the rotary recording medium is easily damaged. On the other hand, the characteristics of the rubber dampers are unstable with respect to changes in the environment such as the temperature and are subject to deterioration as being aged. Further, the chemical resistance of the rubber dampers is poor. Thus, there is also a problem in that the positioning accuracy of the cantilever with respect to the support plate is poor because of the unstable characteristics of the rubber dampers.
A second example of the conventional transducer element assembly comprises a generally triangular cantilever and a transducer element provided on a vertex portion of the triangular cantilever. A pair of conical arms and a permanent magnet are provided on the base portion of the cantilever. A pair of pivots and a permanent magnet are provided on a support plate which is driven and displaced by the actuator. The cantilever is mounted on the support plate so that the pair of conical arms engage corresponding grooves of the pivots on the support plate and the magnet on the cantilever confronts the magnet on the support plate with a gap between the two magnets. Tip ends of the conical arms are pressed against the corresponding grooves of the pivots due to a magnetic attraction between the two magnets. Such a transducer element assembly is disclosed in the U.S. Pat. No. 4,339,812, for example.
According to the second example of the conventional transducer element assembly, the problems of the first example of the conventional transducer assembly are eliminated because no rubber dampers are used. However, it requires complex processing in order to form the conical arms on the cantilever and to form the grooves of the pivots on the support plate. In addition, the conical arms must be mounted on the cantilever with a high precision so that the conical arms will precisely engage the corresponding grooves of the pivots when the cantilever is mounted on the support plate. As a result, there are problems in that the transducer element assembly has a complex construction and is expensive to manufacture. But since especially the cantilever portion of the transducer elmment assembly is a disposable type item which is user replaceable, it is desirable that the construction is simple and requires no complex processes to manufacture. Furthermore, it is desirable that the transducer element assembly can be manufactured at a low cost.